My cousin has a spare 20 gallon tall because he moved his turtles to a larger tank so I'm taking it.

While I clean it up, set it up, and wait for the nitrogen cycle to happen, I am trying to think up what fish I want.

My favorite fish are male bettas, but they're not very community compatible. I've had people tell me they can be, but I don't think I believe them and I don't want the stress of watching a betta like a hawk just in case he goes on a homicidal rampage and I also don't have anywhere to set up yet another tank to separate it and I'm also not very interested in a sorority.

I do want at least some very bright and flashy fish. I got interested in killifish, but they need more acidic water and my water is 7.6 or 7.8 out of the tap and I'm not sure if I want to or can manage changing the pH and keeping it consistent.

I hate guppies at this point (getting rid of every single one of those breeding buggers) and want to avoid them.

I'm interested in having sand and getting some corys for bottom feeders.

The tank will definitely be planted. Thinking of having a dwarf lily as the centerpiece because they're my favorite plant. I will probably throw in bits from my other tanks so it will include some of the following: hornwort, brazilian pennywort, java moss, guppy grass, banana plant, creeping charlie, marimo moss. The plant set-up will be more on the low-light/low-tech side.

I might have driftwood. I like the look of driftwood but everyone in my family complains about the tannins because it makes the aquarium the color of pee for a while.

I'm not great with stocking input - but wanted to say congrats on the 'new' tank, and good luck!!
You can always boil the tannins out of the wood, if you don't want pee-water! ~___^

I personally would want to see corys in a 30" long tank rather than a 24" tank, but as tolak pointed out they can most certainly be kept in a 20. I like his suggestion of the pandas - would go with smaller species, not something like the massive emerald corys

My cousin has a spare 20 gallon tall because he moved his turtles to a larger tank so I'm taking it.

While I clean it up, set it up, and wait for the nitrogen cycle to happen, I am trying to think up what fish I want.

My favorite fish are male bettas, but they're not very community compatible. I've had people tell me they can be, but I don't think I believe them and I don't want the stress of watching a betta like a hawk just in case he goes on a homicidal rampage and I also don't have anywhere to set up yet another tank to separate it and I'm also not very interested in a sorority.

I do want at least some very bright and flashy fish. I got interested in killifish, but they need more acidic water and my water is 7.6 or 7.8 out of the tap and I'm not sure if I want to or can manage changing the pH and keeping it consistent.

I hate guppies at this point (getting rid of every single one of those breeding buggers) and want to avoid them.

I'm interested in having sand and getting some corys for bottom feeders.

The tank will definitely be planted. Thinking of having a dwarf lily as the centerpiece because they're my favorite plant. I will probably throw in bits from my other tanks so it will include some of the following: hornwort, brazilian pennywort, java moss, guppy grass, banana plant, creeping charlie, marimo moss. The plant set-up will be more on the low-light/low-tech side.

I might have driftwood. I like the look of driftwood but everyone in my family complains about the tannins because it makes the aquarium the color of pee for a while.

I think this would be a really good set up. The platies can be very colorful and the betta, if it is a male will be colorful too.
1 Male Betta
4 Platies

I personally would want to see corys in a 30" long tank rather than a 24" tank, but as tolak pointed out they can most certainly be kept in a 20. I like his suggestion of the pandas - would go with smaller species, not something like the massive emerald corys

It took like ten drops for the kh test to change color and 20 for the gh test to change color. So that's 10dKH and the chart on the kit doesn't have 20 drops on it...

I like the rainbowfish, cherry barb, and pygmy cory idea that was suggested, though the pygmy corys prefer things to skew softer so that might be a problem.

And those three are okay with adult shrimp. I have two male shrimp that aren't red in the slightest that need to be separated from my red red cherry shrimp.

How many of each fish would I be able to put in? They need to be in groups but the websites I looked at kind of varied in how many friends these guys need. I would prefer to avoid putting them in the bare minimum tiny group but then tank capacity.

I looked at AqAdvisor and it suggested 5 rainbowfish, 5 cherry barbs, and 4 pygmy corys. But then said it was too much when I added the 2 shrimp.

My dad wants to add zebra nerite snails or some colorful snail because he thinks my olive nerites are boring but he likes the big snails.

First off, where did you find the API GH and KH test solutions? >< I've been searching forever, do you have to order them? =o I had to use the water companies info for the GH, but that doesn't factor in any changes plants, wood and the like in a tank may change. lol

Well, I never listen to those stocking auto idea thingamabobs, they tend to go overboard a lot. I think Rainbows get too big, and cories need groups of five as a minimum. Also...not sure why cherry shrimp pushed it overboard since they barely have a bioload at all and you could do a 50+ member colony in a normal sized ten gallon with a lot of good plants.

Check out if the cherry barbs and pygmy cories will be alright though. Again, really iffy on the cories since they're so active and need to jump up top for air often. x.x

Aqadvisor gives you very conservative stocking limits - definitely a good thing considering who uses such a tool. That's not a bad place to start - from there you can add more if you feel it necessary. I would bump the cherry barbs up to 7 - 3 males and 4 females. It's important to have more than 2 males so that the one is not constantly harassed by the dominant male. Having multiple males also relieves pressure on the females since they will spend time sparring with each other, which is one of the coolest aspect of keeping these fish.